1. Field
Example embodiments relate to apparatuses and/or methods that may read data in memory devices. Also, example embodiments relate to apparatuses and/or methods that may read data in multi-level cell memory devices or multi-bit cell memory devices.
2. Description of Related Art
A single-level cell (SLC) memory device may store one bit of data in a single memory cell. The SLC memory may be referred to as a single-bit cell (SBC) memory. A process of storing one bit of data in a single level cell of the SLC memory device may be referred to as a programming process and may change a threshold voltage of the single level cell. The SLC memory device may have a high threshold voltage level or a low threshold voltage level depending on whether one bit of data stored in the single level cell is “0” or “1”. A process of reading data stored in the single level cell may be performed by determining whether a sensed threshold voltage of the single level cell is greater than or less than a reference voltage level or a read voltage level.
Due to a fine electrical characteristic difference between single level cells, the threshold voltage of each single level cell may have a distribution within a predetermined range. For example, when a sensed threshold voltage of the single level cell is greater than 0.5V and less than 1.5V, it may be determined that data stored in the single bit cell has a logic value of “1”. When the threshold voltage of the single bit cell is greater than 2.5V and less than 3.5V, it may be determined that the data stored in the single bit cell has a logic value of “0”.
A process of sensing the threshold voltage of the single bit cell may be performed by applying a predetermined voltage level to a gate terminal of the single bit cell and sensing the size of current flowing between a source and a drain of the single bit cell.
Meanwhile, a multi-level cell (MLC) memory device that can store data of at least two bits in a single memory cell has been proposed in response to a need for higher integration of memory. The MLC memory device may be referred to as a multi-bit cell (MBC) memory device.